Use only certain info from simple HTML DOM

object(simple_html_dom_node)#240 (9) {
  ["nodetype"]=>
  int(1)
  ["tag"]=>
  string(4) "span"
  ["attr"]=>
  array(1) {
    ["id"]=>
    string(9) "min_price"
  }
  ["children"]=>
  array(0) {
  }
  ["nodes"]=>
  array(1) {
    [0]=>
    object(simple_html_dom_node)#241 (9) {
      ["nodetype"]=>
      int(3)
      ["tag"]=>
      string(4) "text"
      ["attr"]=>
      array(0) {
      }
      ["children"]=>
      array(0) {
      }
      ["nodes"]=>
      array(0) {
      }
      ["parent"]=>
      *RECURSION*
      ["_"]=>
      array(1) {
        [4]=>
        string(5) "2.815"
      }

[“parent”]=>
RECURSION
[“_”]=>
array(1) {
[4]=>
string(5) “2.815”

I want the number, Right now its 2.815 to store as a variable. The number 2.815 changes every 15 minutes.
I want to be able to store the 2.815 and add 10% to it and echo the results.

Anyone know how to handle this?